Announcements 4/6/12 Prayer Exam 3 ends tomorrow I’ll be on the radio 5 pm
tomorrow with the Utah Baroque Ensemble: 89.1 FM or Sirius XM 143 (BYU radio). An hour of classical-style choral music, pieces dating from ~1600 to ~2000.
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Reading Quiz Who developed the “A and B”
coefficients?a. Avogadro and Boltzmannb. Bohrc. Einsteind. Fermi e. Plank
Reading Quiz Which of these processes is not one
considered in Einstein’s A & B coefficient analysis?
a. spontaneous absorptionb. stimulated absorptionc. spontaneous emissiond. stimulated emission
Two Level System: Three Processes
Energy (light, electrical, etc.)
AbsorptionEmission
light
Stimulated Emission
Energy (light)
light: incident + more
A & B for a Two Level System and application to lasers
Lasers
Principal components:1. Gain medium2. Laser pumping energy3. High reflector4. Output coupler5. Laser beam
Image & list from Wikipedia
From Saleh & Teich,
Fundamentals of Photonics
(2007)
From Wikipedia
Lasers!!
From Saleh & Teich, Fundamentals of Photonics (2007)
Semiconductor Alloys
From http://www.tf.uni-kiel.de/matwis/amat/semi_en/kap_5/backbone/r5_1_4.html
Bandgap Engineering
Quotes from web page author